The multi-center research study will evaluate the safety and effectiveness of PROVIGIL as a treatment for sleep apnea patients who are regular users of CPAP and continue to suffer from daytime sleepiness. PROVIGIL is a medication, which is currently prescribed to treat daytime sleepiness in patients with narcolelpsy (an extreme tendency to fall asleep in quiet surroundings or when engaged in monotonous activities). The purpose of the twelve-week open label extension is to continue safety monitoring.